To install an outdoor faucet, tap an interior cold water line, and add piping so it reaches the exterior wall. Mark where the outdoor faucet will be installed, as well as its water line. Dig a trench running from the exterior wall pipe to the outdoor faucet. Run a pipe from the exterior wall line to the faucet. At the end of the trench, install a post, and attach the faucet with the new line running up into it.
The pipe that connects the interior water line to the faucet's pipe should be sturdy copper piping. The faucet line that runs underground should be PEX tubing, which is flexible enough to easily bend but sturdy enough to handle a large flow of water.
Check what type of soil the trench is being dug from. If the soil is hard or rocky, dig a trench about six inches deep and install the pipe. If the soil is soft, dig a trench about 12 inches deep and install the pipe. Cover the pipe with about 2 inches of dry soil and then 2 inches layer of concrete mix. Fill the rest of the trench with dry soil, which helps dry the wet concrete. Be sure to check for utility lines when digging.
To install the faucet post, get a length of PVC pipe, and cut it to the desired height. Run the PEX tubing up through the PVC pipe. Mount the faucet head on the PVC pipe, and connect the PEX tubing to it. Stabilize the PVC post with cement and soil.